DESCRIPTION: The overall objective of this proposal is to test the hypothesis that continuous exposure to EMF can induce or promote brain tumor incidence in animals, either independent of or in association with, the carcinogenic effects of ionizing irradiation. The objective will be addressed through four specific aims. The first is to assess the time-dependent incidence of brain toxic injury in normal mice with and without continuous EMF exposure. The second is to define the time-dependent incidence of primary brain tumors in normal mice with and without continuous EMF exposure. The third is to determine the time-dependent incidence of primary brain tumors in radiation-treated mice with and without continuous EMF exposure. The fourth is to examine the time-dependent incidence of lymphoma involvement of the brain in control and radiation-treated mice with and without continuous EMF exposure. It is anticipated that these studies will lead to the development of an important model system to define the nature and basic mechanisms of EMF effects on brain cancer incidence.